In one aspect, the invention relates to a process for producing carbon black. In another aspect, the invention relates to an apparatus for producing carbon black.
"Hard" or tread type carbon blacks having a surface area in the range of from about 70 to about 125 m.sup.2 /g as measured by the CTAB method are usually produced by using a different process and reactor than that used for the production of "soft" or carcass type carbon black having a CTAB surface area in the range of about 25 to about 70 m.sup.2 /g. The necessity of having different reactors for different products is burdensome for carbon black plants and the desirability of a single reactor which could produce both types of blacks is manifest. Also, it has been noted that the yield of "soft" carbon blacks on the basis of oil feedstock used is generally lower than theoretical yield. A soft black reactor that provides higher yield or efficiency could provide cheaper product, and would thus be very desirable.
Grit is another problem in carbon black production. High grit levels in the carbon black product sometimes requires the purchase of micropulverizers as plant equipment. Grit is believed by some to have an adverse impact on compounding carbon black into rubber as well as eroding compounding equipment. Clearly a reactor and process that provide low grit levels in the carbon black product would be desirable.
A reactor which operates in a stable manner is clearly very desirable. The various process inputs must be changed when it is desired to switch over to a new product and the ability to duplicate earlier runs can provide substantial savings in manpower and reduce production of off-specification product.